Flash mobbing phenomenon

What is the meaning of flash mobbing, why do people decide to practise it and of what means has it got to do with the society.

From Rome to London, New York to Tokyo, the flash mobbing phenomenon is growing every day. Ealier this year, more than 30 flash mobbers in Berlin shouted ‘YES, yes!’ into their mobile phones in the middle of a crowded street. The next week, in Dortmund, 24 flash mobbers gathered outside a depertment store. They stared at a washing machine, while eating bananas, for five minutes.
And yesterday afternoon, in New York, more than 250 people gathered on the 16th Street Mall and played an imaginary game of table tennis, or ping pong.
The original instruction were on online message boards. People then posted the instruction to friends via message or emails. The instruction asked people to go to the Mall and look for secret information from people with balloons.
At 5:37 the group divided into two. One group stayer on the round floor, the other moved the top floor. Then one group shouted ‘Ping!’ and the other group shouted ‘Pong!’ They continued this for ten minutes then suddenly stopped and left.

So what is flash mobbing? Well, flash mobs are sudden gathering of people at a predetermined location at a predetermined time. People do something according to a written script, then quickly go away. But why do they do it? Organisers say there is no point to flash mobbing. It has no political or commercial aspect: flash mobbing is just fun!